Digital terrain model (DTM) presents a set of georeferenced data characterizing geometric properties of relief (i. e. elevation and morphometric characteristics) that are computed from input elevation points using interpolation method. The accuracy of input data, interpolation method and spatial resolution of output rasters are factors determining the quality of the results. One of the most appropriate interpolation algorithms for environmental applications is the regularized spline with tension. This method was applied for computation of the DTM of Slovakia with spatial resolution of 25 meters and for DTMs at detailed scales. The examples of environmental DTM applications are presented. They relate to the wide spectrum of methods of mapping, spatial data inventory, analysis, modeling and visualization.